projects / unix-history / blame
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1 | /* |
| 2 | * Copyright (c) 1986 Regents of the University of California. | |
| 3 | * All rights reserved. | |
| 4 | * | |
| 5 | * This code is derived from software contributed to Berkeley by | |
| 6 | * Computer Consoles Inc. | |
| 7 | * | |
| 1c15e888 C |
8 | * Redistribution and use in source and binary forms are permitted |
| 9 | * provided that: (1) source distributions retain this entire copyright | |
| 10 | * notice and comment, and (2) distributions including binaries display | |
| 11 | * the following acknowledgement: ``This product includes software | |
| 12 | * developed by the University of California, Berkeley and its contributors'' | |
| 13 | * in the documentation or other materials provided with the distribution | |
| 14 | * and in all advertising materials mentioning features or use of this | |
| 15 | * software. Neither the name of the University nor the names of its | |
| 16 | * contributors may be used to endorse or promote products derived | |
| 17 | * from this software without specific prior written permission. | |
| 18 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR | |
| 19 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED | |
| 20 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
| 1f0502d3 KB |
21 | */ |
| 22 | ||
| 23 | #if defined(SYSLIBC_SCCS) && !defined(lint) | |
| 1c15e888 | 24 | .asciz "@(#)cvtfl.s 1.3 (Berkeley) 6/1/90" |
| 1f0502d3 | 25 | #endif /* SYSLIBC_SCCS and not lint */ |
| 61051f6a SL |
26 | |
| 27 | #include <tahoemath/fp.h> | |
| 28 | #include "DEFS.h" | |
| 29 | ||
| 30 | XENTRY(cvtfu, R2|R3|R4|R5) | |
| 31 | jbr 1f | |
| 32 | ||
| 33 | XENTRY(cvtfl, R2|R3|R4|R5) | |
| 34 | # | |
| 35 | #Some initializations: | |
| 36 | # | |
| 37 | 1: | |
| 38 | movl 4(fp),r0 # fetch operand. | |
| 39 | clrl r3 # r3 - negative flag. | |
| 40 | # | |
| 41 | #get exponent | |
| 42 | # | |
| 43 | andl3 $EXPMASK,r0,r2 # r2 will hold the exponent. | |
| 44 | jeql is_reserved # check for reserved operand. | |
| 45 | cmpl $ONE_EXP,r2 # if exponent is less then 1,return zero. | |
| 46 | jgtr retzero | |
| 47 | andl2 $0!EXPSIGN,r2 # turn off biased exponent sign | |
| 48 | shrl $EXPSHIFT,r2,r2 | |
| 49 | # | |
| 50 | #get fraction | |
| 51 | # | |
| 52 | bbc $31,r0,positive # if negative remember it. | |
| 53 | incl r3 | |
| 54 | positive: | |
| 55 | # clear the non fraction parts. | |
| 56 | andl2 $(0!(EXPMASK | SIGNBIT)),r0 | |
| 57 | # add the hidden bit. | |
| 58 | orl2 $(0!CLEARHID),r0 | |
| 59 | subl2 $24,r2 # compute the shift. | |
| 60 | jgtr shift_left | |
| 61 | mnegl r2,r2 | |
| 62 | shrl r2,r0,r0 # shift right. | |
| 63 | jmp shifted | |
| 64 | shift_left: | |
| 65 | cmpl r2,$7 | |
| 66 | jgtr overflow | |
| 67 | go_on: shll r2,r0,r0 # shift right. | |
| 68 | shifted: | |
| 69 | bbc $0,r3,done # check for negative | |
| 70 | mnegl r0,r0 | |
| 71 | done: | |
| 72 | ret | |
| 73 | ||
| 74 | retzero: | |
| 75 | clrl r0 | |
| 76 | ret | |
| 77 | overflow: | |
| 78 | callf $4,sfpover | |
| 79 | jmp go_on | |
| 80 | ||
| 81 | is_reserved: | |
| 82 | bbc $31,r0,retzero | |
| 83 | ||
| 84 | callf $4,sfpresop | |
| 85 | ret |